&RQILJXULQJ
S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
5-28 A5E00105492-03
 6HOHFWLQJWKH/RDG3RZHU6XSSO\
7DVNRIORDGSRZHUVXSSO\
The load power supply feeds the input and output circuits (load circuits), and the
sensors and actuators.
&KDUDFWHULVWLFVRIORDGSRZHUVXSSO\XQLWV
You will have to adapt the load power supply unit to your specific application. The
following table compares the various load power supply units and their
characteristics to help you make your choice:
Table 5-12 Characteristics of load power supply units
0DQGDWRU\IRU &KDUDFWHULVWLFVRIWKHORDG
SRZHUVXSSO\
5HPDUNV
Modules requiring voltage
supplies of ≤ 60 VDC or ≤ 25
VAC.
24 VDC load circuits
Protective separation These characteristics apply
to Siemens power supplies
of the series PS 307 and to
SITOP power (series 6EP1).
24 VDC load circuits
48 VDC load circuits
60 VDC load circuits
Output voltage tolerances:
20.4 V to 28.8 V
40.8 V to 57.6 V
51 V to 72 V
-
5HTXLUHPHQWVIRUORDGSRZHUVXSSOLHV
It must provide an extra-low voltage of ≤ 60 VDC and be safely isolated from
mains. Safe isolation from mains can be realized, for example, in accordance with
VDE 0100 Part 410 / HD 384-4-41 / IEC 364-4-41 (as functional extra-low voltage
with safe isolation) or VDE 0805 / EN 60950 / IEC 950 (as safety extra-low voltage
SELV) or VDE 0106 Part 101.
+RZWRGHWHUPLQHORDGFXUUHQW
The required load current is determined by the sum load current of all sensors and
actuators connected to the outputs.
In case of short-circuit the DC outputs are briefly loaded with twice to three times
the rated output current before the clocked electronic short-circuit protection comes
into effect. Thus, you must consider this increased short-circuit current when
selecting your load power supply unit. Uncontrolled load power supplies usually
provide this excess current. With controlled load power supplies - especially for low
output power (up to 20 A) - you must ensure that the supply can handle this excess
current.
To Next Page
Loading...
Need help?
General
